[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #16 from kargl at gcc dot gnu.org ---
Author: kargl
Date: Tue Nov 22 18:25:55 2016
New Revision: 242717

URL: https://gcc.gnu.org/viewcvs?rev=242717=gcc=rev
Log:
2016-11-22  Steven G. Kargl  

PR fortran/58001
* io.c (next_char_not_space): Update handling of a 'tab' in a FORMAT.
(format_lex): Adjust invocations of next_char_not_space().

2016-11-22  Steven G. Kargl  

PR fortran/58001
* gfortran.dg/fmt_tab_1.f90: Adjust testcase.
* gfortran.dg/fmt_tab_2.f90: Ditto.

Modified:
branches/gcc-6-branch/gcc/fortran/ChangeLog
branches/gcc-6-branch/gcc/fortran/io.c
branches/gcc-6-branch/gcc/testsuite/ChangeLog
branches/gcc-6-branch/gcc/testsuite/gfortran.dg/fmt_tab_1.f90
branches/gcc-6-branch/gcc/testsuite/gfortran.dg/fmt_tab_2.f90

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

kargl at gcc dot gnu.org changed:

   What|Removed |Added

 Status|WAITING |RESOLVED
 Resolution|--- |FIXED
   Assignee|unassigned at gcc dot gnu.org  |kargl at gcc dot gnu.org
   Target Milestone|--- |7.0

--- Comment #15 from kargl at gcc dot gnu.org ---
Fixed on trunk.

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #14 from kargl at gcc dot gnu.org ---
Author: kargl
Date: Thu Nov 17 00:18:18 2016
New Revision: 242530

URL: https://gcc.gnu.org/viewcvs?rev=242530=gcc=rev
Log:
2016-11-16  Steven G. Kargl  

PR fortran/58001
* io.c (next_char_not_space): Update handling of a 'tab' in a FORMAT.
(format_lex): Adjust invocations of next_char_not_space().

2016-11-16  Steven G. Kargl  

PR fortran/58001
* gfortran.dg/fmt_tab_1.f90: Adjust testcase.
* gfortran.dg/fmt_tab_2.f90: Ditto.

Modified:
trunk/gcc/fortran/ChangeLog
trunk/gcc/fortran/io.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gfortran.dg/fmt_tab_1.f90
trunk/gcc/testsuite/gfortran.dg/fmt_tab_2.f90

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

kargl at gcc dot gnu.org changed:

   What|Removed |Added

 CC||kargl at gcc dot gnu.org

--- Comment #13 from kargl at gcc dot gnu.org ---
(In reply to Dominique d'Humieres from comment #11)
> > What happened with patch in comment 9?
> 
> PING!

I've posted an updated patch that includes Manuel's
comment #12.

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

Manuel López-Ibáñez  changed:

   What|Removed |Added

 CC||manu at gcc dot gnu.org

--- Comment #12 from Manuel López-Ibáñez  ---
(In reply to Steve Kargl from comment #9)
> +  if (!gfc_option.warn_tabs && c == '\t')
> +   gfc_warning ("Nonconforming tab character in FORMAT at %C");
>  }

Nowadays, this would be:

if (c == '\t')
 gfc_warning (OPT_Wtabs, Nonconforming tab character in FORMAT at %C");

Cheers,

Manuel.

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

Dominique d'Humieres  changed:

   What|Removed |Added

 CC||kargl at gcc dot gnu.org

--- Comment #11 from Dominique d'Humieres  ---
> What happened with patch in comment 9?

PING!

[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

Dominique d'Humieres  changed:

   What|Removed |Added

 Status|NEW |WAITING

--- Comment #10 from Dominique d'Humieres  ---
What happened with patch in comment 9?

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[sgk at troutmask dot apl.washington.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #9 from Steve Kargl sgk at troutmask dot apl.washington.edu ---
The following patch causes gfortran to treat a tab within
a FORMAT statement that same as it does elsewhere for the
appearance of a nonconforming use of tab.  The two tet
cases have been adjusted.

Index: gcc/fortran/io.c
===
--- gcc/fortran/io.c(revision 201382)
+++ gcc/fortran/io.c(working copy)
@@ -192,23 +192,14 @@ unget_char (void)
 /* Eat up the spaces and return a character.  */

 static char
-next_char_not_space (bool *error)
+next_char_not_space ()
 {
   char c;
   do
 {
   error_element = c = next_char (NONSTRING);
-  if (c == '\t')
-{
-  if (gfc_option.allow_std  GFC_STD_GNU)
-gfc_warning (Extension: Tab character in format at %C);
-  else
-{
-  gfc_error (Extension: Tab character in format at %C);
-  *error = true;
-  return c;
-}
-}
+  if (!gfc_option.warn_tabs  c == '\t')
+  gfc_warning (Nonconforming tab character in FORMAT at %C);
 }
   while (gfc_is_whitespace (c));
   return c;
@@ -226,7 +217,6 @@ format_lex (void)
   char c, delim;
   int zflag;
   int negative_flag;
-  bool error = false;

   if (saved_token != FMT_NONE)
 {
@@ -235,7 +225,7 @@ format_lex (void)
   return token;
 }

-  c = next_char_not_space (error);
+  c = next_char_not_space ();

   negative_flag = 0;
   switch (c)
@@ -245,7 +235,7 @@ format_lex (void)
   /* Falls through.  */

 case '+':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (!ISDIGIT (c))
 {
   token = FMT_UNKNOWN;
@@ -256,7 +246,7 @@ format_lex (void)

   do
 {
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (ISDIGIT (c))
 value = 10 * value + c - '0';
 }
@@ -286,7 +276,7 @@ format_lex (void)

   do
 {
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (ISDIGIT (c))
 {
   value = 10 * value + c - '0';
@@ -321,7 +311,7 @@ format_lex (void)
   break;

 case 'T':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   switch (c)
 {
 case 'L':
@@ -349,7 +339,7 @@ format_lex (void)
   break;

 case 'S':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (c != 'P'  c != 'S')
 unget_char ();

@@ -357,7 +347,7 @@ format_lex (void)
   break;

 case 'B':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (c == 'N' || c == 'Z')
 token = FMT_BLANK;
   else
@@ -419,7 +409,7 @@ format_lex (void)
   break;

 case 'E':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (c == 'N' )
 token = FMT_EN;
   else if (c == 'S')
@@ -449,7 +439,7 @@ format_lex (void)
   break;

 case 'D':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   if (c == 'P')
 {
   if (!gfc_notify_std (GFC_STD_F2003, DP format 
@@ -472,7 +462,7 @@ format_lex (void)
   break;

 case 'R':
-  c = next_char_not_space (error);
+  c = next_char_not_space ();
   switch (c)
 {
 case 'C':
@@ -513,9 +503,6 @@ format_lex (void)
   break;
 }

-  if (error)
-return FMT_ERROR;
-
   return token;
 }

Index: gcc/testsuite/gfortran.dg/fmt_tab_1.f90
===
--- gcc/testsuite/gfortran.dg/fmt_tab_1.f90(revision 201382)
+++ gcc/testsuite/gfortran.dg/fmt_tab_1.f90(working copy)
@@ -1,6 +1,9 @@
-! { dg-do run }
+! { dg-do compile }
+! { dg-options -Wtabs }
 ! PR fortran/32987
   program TestFormat
 write (*, 10)
- 10 format ('Hello ','bug!') ! { dg-warning Extension: Tab character
in format }
+! There is a tab character before 'bug'.  This is accepted without
+! the -Wno-tabs option or a -std= option.
+ 10 format ('Hello ','bug!')
   end
Index: gcc/testsuite/gfortran.dg/fmt_tab_2.f90
===
--- gcc/testsuite/gfortran.dg/fmt_tab_2.f90(revision 201382)
+++ gcc/testsuite/gfortran.dg/fmt_tab_2.f90(working copy)
@@ -2,6 +2,6 @@
 ! { dg-options -std=f2003 }
 ! PR fortran/32987
   program TestFormat
-write (*, 10) ! { dg-error FORMAT label 10 at .1. not defined }
- 10 format ('Hello ','bug!') ! { dg-error Extension: Tab character in
format }
+write (*, 10)
+ 10 format ('Hello ','bug!') ! { dg-warning tab character in FORMAT
}
   end

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

Dominique d'Humieres dominiq at lps dot ens.fr changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2013-07-30
 Ever confirmed|0   |1

--- Comment #2 from Dominique d'Humieres dominiq at lps dot ens.fr ---
Compiling the following code with -Wtabs

  print *, AstringwithTabsinsteadofspaces
print 1894
1894  format('123')
  end

gives

pr58001.f90:3.14:

1894  format( '123')
  1
Warning: Extension: Tab character in format at (1)

If compiled with -Wno-tabs, it gives

pr58001.f90:2.1:

 print 1894
 1
Warning: Nonconforming tab character at (1)
pr58001.f90:3.14:

1894  format( '123')
  1
Warning: Nonconforming tab character at (1)
pr58001.f90:3.14:

1894  format( '123')
  1
Warning: Extension: Tab character in format at (1)

Is this the expected behavior?-(I was expecting the later output for -Wtabs,
and no warning with -Wno-tabs: on most options Wno-* suppress the warnings for
the corresponding option.)

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[sgk at troutmask dot apl.washington.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #3 from Steve Kargl sgk at troutmask dot apl.washington.edu ---
On Tue, Jul 30, 2013 at 12:59:00PM +, dominiq at lps dot ens.fr wrote:
 
   print *, AstringwithTabsinsteadofspaces
 print 1894
 1894  format('123')
   end
 

According to both vi and nedit, there are no tabs in the
above code.  I assume that this is cut-n-paste from an
xterm term.

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #4 from Dominique d'Humieres dominiq at lps dot ens.fr ---
 According to both vi and nedit, there are no tabs in the
 above code.  I assume that this is cut-n-paste from an
 xterm term.

With Safari I see the tabs in comment #2, but not in what has been pasted in
comment #3. I am attaching the code.

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #5 from Dominique d'Humieres dominiq at lps dot ens.fr ---
Created attachment 30573
  -- http://gcc.gnu.org/bugzilla/attachment.cgi?id=30573action=edit
test case with tabs

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[sgk at troutmask dot apl.washington.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #6 from Steve Kargl sgk at troutmask dot apl.washington.edu ---
On Tue, Jul 30, 2013 at 12:59:00PM +, dominiq at lps dot ens.fr wrote:
 
 If compiled with -Wno-tabs, it gives
 
 pr58001.f90:2.1:
 
  print 1894
  1
 Warning: Nonconforming tab character at (1)
 pr58001.f90:3.14:
 
 1894  format( '123')
   1
 Warning: Nonconforming tab character at (1)
 pr58001.f90:3.14:
 
 1894  format( '123')
   1
 Warning: Extension: Tab character in format at (1)
 
 Is this the expected behavior?

With -Wno-tabs, gfortran should report a warning for the
occurence of every tab used in the context of a character
from the Fortran character set.  Taking your code, which I've
deleted here, and replace all whitespace by tabs, I get the
expected number of warnings.  Historically, I wanted to use
-Wtabs as you expected, but there was too much wailing on 
the gfortran lists, so it was changed to -Wno-tabs with the
meaning that no tabs are allowed in the context of the
Fortran character set.  You'll notice that tabs within
a literal character string are not flagged.  The history
of -Wtabs verse -Wno-tabs can be found in the mailinglist
archive.

Now, for the problem at hand, it seems that there is a
bug in io.c.   Here the code in question:


/* Eat up the spaces and return a character.  */

static char
next_char_not_space (bool *error)
{
  char c;
  do
{
  error_element = c = next_char (NONSTRING);
  if (c == '\t')
{
  if (gfc_option.allow_std  GFC_STD_GNU)
gfc_warning (Extension: Tab character in format at %C);
  else
{
  gfc_error (Extension: Tab character in format at %C);
  *error = true;
  return c;
}
}
}
  while (gfc_is_whitespace (c));
  return c;
}

Notice that there is no check for gfc_option.warn_tabs.

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #7 from Dominique d'Humieres dominiq at lps dot ens.fr ---
 With -Wno-tabs, gfortran should report a warning for the
 occurence of every tab used in the context of a character
 from the Fortran character set.  Taking your code, which I've
 deleted here, and replace all whitespace by tabs, I get the
 expected number of warnings.  Historically, I wanted to use
 -Wtabs as you expected, but there was too much wailing on 
 the gfortran lists, so it was changed to -Wno-tabs with the
 meaning that no tabs are allowed in the context of the
 Fortran character set.  You'll notice that tabs within
 a literal character string are not flagged.

I cannot understand the rationale of this choice, but I guess it's too late to
change it!-(

 The history of -Wtabs verse -Wno-tabs can be found in the mailinglist
 archive.

No interest to dig the archives on this issue.

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[sgk at troutmask dot apl.washington.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #8 from Steve Kargl sgk at troutmask dot apl.washington.edu ---
On Tue, Jul 30, 2013 at 06:16:27PM +, dominiq at lps dot ens.fr wrote:
 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001
 
 --- Comment #7 from Dominique d'Humieres dominiq at lps dot ens.fr ---
  With -Wno-tabs, gfortran should report a warning for the
  occurence of every tab used in the context of a character
  from the Fortran character set.  Taking your code, which I've
  deleted here, and replace all whitespace by tabs, I get the
  expected number of warnings.  Historically, I wanted to use
  -Wtabs as you expected, but there was too much wailing on 
  the gfortran lists, so it was changed to -Wno-tabs with the
  meaning that no tabs are allowed in the context of the
  Fortran character set.  You'll notice that tabs within
  a literal character string are not flagged.
 
 I cannot understand the rationale of this choice, but I guess it's too late to
 change it!-(
 
  The history of -Wtabs verse -Wno-tabs can be found in the mailinglist
  archive.
 
 No interest to dig the archives on this issue.

http://gcc.gnu.org/ml/fortran/2006-03/msg00226.html

[Bug fortran/58001] Make it possible to silence Extension: Tab character in format warning

[kargl at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

kargl at gcc dot gnu.org changed:

   What|Removed |Added

 CC||kargl at gcc dot gnu.org

--- Comment #1 from kargl at gcc dot gnu.org ---
(In reply to Tobias Burnus from comment #0)
 For indenting the source code, gfortran warns only with -std=f* or with
 -Wtab.

Please, check the archive.  At one time gfortran would issue a warning
if a tab was used in a nonconforming context.  Too many people were
upset about this, so the -W[no-]tab option, which has a convoluted history,
was the compromise.

 However, for format strings, it always warns - and with -std=f* it even
 turns the warning into an error! (see io.c's next_char_not_space)
 
 Example:
 
 1894  format(   '123')
   end
 
 (The tab is before '123'. A tab in the string itself is not warned for.)
 
 Maybe the best would be to disable this warning with -std=legacy - and refer
 to -std=legacy in the -std=gnu warning?

Tab is not and never has been a member of the Fortran character set.
The above line of code is nonconforming.  Gfortran, IMNSHO, should
always issue an error, but I lost that battle years ago.